Characteristics of cathodic polarization at Pt/YSZ interface without the effect of electrode microstructure

Sung Pil Yoon, SukWoo Nam, Seung Goo Kim, Seong Ahn Hong, Sang Hoon Hyun

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

The characteristics of cathodic polarization at the Pt/yttria stabilized zirconia (YSZ) interface have been evaluated with different electrode microstructures by ac impedance analysis. The measurements were carried out at the temperatures of 873-1273 K and oxygen partial pressure (PO2) in the range of 0.01-1 atm. From the results of impedance analysis, it was found that gas phase diffusion can be involved in two different ways, such as boundary-layer diffusion and pore diffusion. When the gas phase diffusion was effectively eliminated from the total electrode resistance (Rel), we observed the same dependences of temperature and oxygen partial pressure regardless of their different electrode microstructures. In the high temperature (1073-1273 K) and low oxygen partial pressure regions (<0.01 atm PO2), the cathode reactions included two major reactions: gas phase diffusion and direct adsorption reaction. In direct adsorption reaction oxygen molecules are directly adsorbed from the gas phase and dissociate on oxygen vacancies, which are located at the triple phase boundaries (TPB). In the low temperature (<973 K) and high oxygen partial pressure region (∼1 atm PO2), the cathode reaction is dominated by the dissociation of oxygen molecules at the Pt/YSZ interface.

Original languageEnglish
Pages (from-to)27-34
Number of pages8
JournalJournal of Power Sources
Volume115
Issue number1
DOIs
Publication statusPublished - 2003 Mar 27
Externally publishedYes

Keywords

  • Cathode reaction
  • Electrode microstructure
  • Impedance analysis
  • Pt/YSZ interface
  • Solid oxide fuel cell

ASJC Scopus subject areas

  • Electrochemistry
  • Fuel Technology
  • Materials Chemistry
  • Energy (miscellaneous)

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